Ponències/Comunicacions de congressoshttp://hdl.handle.net/2117/7278
Sun, 02 Aug 2015 18:39:53 GMT2015-08-02T18:39:53ZToward new controller design paradigms in networked control systemshttp://hdl.handle.net/2117/27568
Toward new controller design paradigms in networked control systems
Torres Guerrero, Gina; Velasco García, Manel; Martí Colom, Pau; Fuertes Armengol, José Mª
One of the main concerns in the design of networked control systems (NCS’s) is the inherent delays induced by the networking infrastructure. Rather than considering delays as a threat, delays may be considered as an opportunity for novel controller design procedures, where delays become a design parameter. The benefits may range from easier and cheaper implementations to improved performance. To enable procedures where the explicit specification of a delay may be profitable, al- ternative models for a discrete-time LTI system with an arbitrary delay used for controller design must be investigated. This paper presents a modeling effort different than the common approach of extending the state-space model with new state variables. The new model is also capable of representing the same system with a delay but using a state-space modeling structure that keeps the original system order. The focus of the paper is to show that both models are equivalent. A direct consequence is that it will be possible to design a controller for a system without delay in such a way that the closed loop system behaves like having a delay. In other words, a relation between desired control performance (via e.g. closed-loop system poles), controller, and delay is established, which provides a new design criterion for NCS
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/2117/275682014-01-01T00:00:00ZDeveloping professional skills at tertiary level: A model to integrate competencies across the curriculumhttp://hdl.handle.net/2117/25103
Developing professional skills at tertiary level: A model to integrate competencies across the curriculum
Sánchez Carracedo, Fermín; Soler Cervera, Antonia; López Álvarez, David; Martín Escofet, Carme; Ageno Pulido, Alicia; Belanche Muñoz, Luis Antonio; Cabré Garcia, José M.; Cobo Valeri, Erik; Farré Cirera, Rafael; García Almiñana, Jordi; Marès Martí, Pere
In the context of the European Higher Education Area, curriculum design needs to be based on the defined competencies of each degree programs, including both domain specific and professional competencies. In this educational context, developing students’ professional skills poses a new challenge we need to face. The present work proposes a model to globally develop professional skills in an Engineering degree program. Based on competency maps, this model allows careful analysis, revision and iteration for an effective integration of professional skills. We define each competency in terms of “dimensions” (or sub-skills), which are further defined according to three-level objectives. Competency maps are built showing the specific graded objectives, which allows to integrate them most finely into degree subjects. A global competency map is also designed including the objectives to be achieved throughout the degree. This global map becomes a useful tool for curriculum designers and coordinators. It allows them to optimize the workload, and to make adjustments most effectively, helping students develop the defined competencies as a global comprehensive experience. To illustrate our model, we explain how it has been implemented to integrate “Communication skills” into subjects, and how the model has been applied to assess “Appropriate attitude towards work” skills.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/2117/251032014-01-01T00:00:00ZMixing local and distributed reactive power control for balancing inverters' effort in grid-connected photovoltaic systemshttp://hdl.handle.net/2117/24370
Mixing local and distributed reactive power control for balancing inverters' effort in grid-connected photovoltaic systems
Velasco García, Manel; Martí Colom, Pau; Camacho Santiago, Antonio; Miret Tomàs, Jaume; Castilla Fernández, Miguel
Reactive power control methods have been proven to be a successful technique for maintaining voltages of photovoltaic (PV) distributed generators (DG) within the admissible limits without enforcing to reduce the production of active power. Usually the control goal is achieved at the expenses of stressing PV inverters unequally. As a consequence, inverters deteriorate at different velocities. This paper presents a mixed local and distributed control strategy that aims at balancing the effort posed by each inverter while achieving the control goal. The local control is a drop-like method that locates inverters' voltages within the permissible voltage levels. Simultaneously, the distributed control, making use of a communication infrastructure, is in charge of driving the DG system to the point where all connected inverters inject the same current, thus balancing the stress between them.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/2117/243702013-01-01T00:00:00ZAn alternative discrete-time model for networked control systems with time delay less than the sampling periodhttp://hdl.handle.net/2117/22838
An alternative discrete-time model for networked control systems with time delay less than the sampling period
Torres Guerrero, Gina; Velasco García, Manel; Martí Colom, Pau; Martín Rull, Enric Xavier; Fuertes Armengol, José Mª
The majority of existing Networked Control Systems (NCS) models are discrete-time formulations based on the exact discretization of the continuous-time linear plant over a sample interval. In the state-space formalism, standard control
textbooks suggest that a simple approach to model discrete-time LTI systems with time delay shorter or equal than the sampling
period is to extend the state vector with a new state variable representing the last control signal, which implies increasing the
order of the model by one. In this paper an alternative state-space model for discrete-time LTI systems with time delay is introduced that does not require increasing the order of the model. The relation between both the standard model and the new model
is established, and the potential benefits of the new model with respect to the standard one are discussed. Numerical examples illustrate the concepts discussed throughout the paper.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/2117/228382013-01-01T00:00:00ZMixing local and distributed reactive power control for balancing inverters’ effort in grid-connected photovoltaic systemshttp://hdl.handle.net/2117/21470
Mixing local and distributed reactive power control for balancing inverters’ effort in grid-connected photovoltaic systems
Velasco García, Manel; Martí Colom, Pau; Camacho Santiago, Antonio; Miret Tomàs, Jaume; Castilla Fernández, Miguel
Reactive power control methods have been proven to be a successful technique for maintaining voltages of photo-voltaic (PV) distributed generators (DG) within the admissible limits without enforcing to reduce the production of active power. Usually the control goal is achieved at the expenses of stressing PV inverters unequally. As a consequence, inverters
deteriorate at different velocities. This paper presents a mixed local and distributed control strategy that aims at balancing the
effort posed by each inverter while achieving the control goal.
The local control is a drop-like method that locates inverters’voltages within the permissible voltage levels. Simultaneously,
the distributed control, making use of a communication infrastructure, is in charge of driving the DG system to the point where all connected inverters inject the same current, thus balancing the stress between them.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/2117/214702013-01-01T00:00:00ZControl strategies based on effective power factor for distributed generation power plants during unbalanced grid voltagehttp://hdl.handle.net/2117/21151
Control strategies based on effective power factor for distributed generation power plants during unbalanced grid voltage
Camacho Santiago, Antonio; Castilla Fernández, Miguel; Miret Tomàs, Jaume; Matas Alcalá, José; Guzmán Solà, Ramon; de Sousa Pérez, Óscar; Martí Colom, Pau; García de Vicuña Muñoz de la Nava, José Luis
Unbalanced voltages in three-phase power systems is a common perturbation propagated along the grid. Distributed Generation plants have gained widespread attention due to their capability to improve power quality in a distributed manner, including voltage unbalance mitigation. A conventional control strategy to command power plants during balanced grid voltages, is the use of power factor to inject/absorb reactive power depending on grid conditions. Advanced control strategies during unbalanced grid voltages can be selected prioritizing positive or negative sequence active and reactive power. This selection determines the voltage support service and therefore can improve the voltage profile, i.e. phase-voltages can be properly supported and voltage imbalance simultaneously corrected. Based on the definition of effective power factor in IEEE 1459 Standard, the reactive power needed for any control strategy is obtained and the resulting effects are described.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/2117/211512013-01-01T00:00:00ZPower sharing control in islanded microgrid using event driven communicationhttp://hdl.handle.net/2117/21150
Power sharing control in islanded microgrid using event driven communication
de Sousa Pérez, Óscar; Miret Tomàs, Jaume; Camacho Santiago, Antonio; Martí Colom, Pau; Guzmán Solà, Ramon
This paper presents a novel power sharing control
strategy for islanded mode microgrids (MG). The goal is to
enable renewable power sources connected to the point of com-
mon coupling (PCC) through three-phase three-wire inverters to
cooperatively feed linear and non-linear local loads. The strategy
contribution is two-fold. First, a centralized controller is designed
to facilitate the power sharing capability of all inverters by means
of data communications regardless of load changes and inverter
faults. Second, a communication protocol is designed following
an event-driven paradigm in such a way that the consumed
bandwidth is reduced. Selected simulation results show the main
features of the power sharing control strategy.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/2117/211502013-01-01T00:00:00ZDistributed reactive power control methods to avoid voltage rise in grid-connected photovoltaic power generation systemshttp://hdl.handle.net/2117/20254
Distributed reactive power control methods to avoid voltage rise in grid-connected photovoltaic power generation systems
Martí Colom, Pau; Velasco García, Manel; Fuertes Armengol, José Mª; Camacho Santiago, Antonio; Miret Tomàs, Jaume; Castilla Fernández, Miguel
A high density of grid-connected photovoltaic (PV)
power generation systems is expected to occur in urban areas.
The connection of distributed generation (DG) may cause serious
problems in the distribution system such as voltage rise. Several
voltage control strategies exist to avoid the over-voltage at
the power grid. In particular, reactive power control methods
have been proved to successfully bring DGs voltages within the
admissible voltage range without reducing the production of
active power. In addition, the possible use of communication
infrastructure to link DGs opens up the development of new
reactive power control methods where control actions at each
DG may be decided using both local and global information.
This paper presents a comparative study of existing and novel
distributed reactive power control methods that have been
designed exploiting the information exchange facility provided
by a communication infrastructure.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/2117/202542013-01-01T00:00:00ZDesigning a practical course in networked control systemshttp://hdl.handle.net/2117/18161
Designing a practical course in networked control systems
Fuertes Armengol, José Mª; Villa Millaruelo, Ricardo; Ayza Graells, Jordi; Marès Martí, Pere; Martí Colom, Pau; Velasco García, Manel; Yépez Castillo, José Gregorio; Torres Guerrero, Gina; Perelló, Miquel
This paper presents a hands-on course in networked control systems (NCS) to be integrated in the education of embedded control systems engineers. The course activities have a strong practical component and most of them are applied exercises to be implemented in a NCS setup. The paper describes the experimental setup and then proposes several activities that can be shaped into a course program according to the needs and diverse background of the targeted audience.
Sun, 01 Jan 2012 00:00:00 GMThttp://hdl.handle.net/2117/181612012-01-01T00:00:00ZHands-on course in networked control systemshttp://hdl.handle.net/2117/17581
Hands-on course in networked control systems
Fuertes Armengol, José Mª; Villa Millaruelo, Ricardo; Ayza Graells, Jordi; Marès Martí, Pere; Martí Colom, Pau; Velasco García, Manel; Yepez, J.; Torres Guerrero, Gina; Perello, M.
In many industrial robotic applications there is a need to
track periodic reference signals and/or reject periodic disturbances. This
paper presents a novel repetitive control design for systems with constant
time-delays in both forward and feedback control channels. An additional
delay is introduced together with plant delays to construct an internal
model for periodic signals, and a simple proportional control is utilized
to stabilize the closed-loop system. Sufficient stability conditions of the
closed-loop system and the robustness analysis under modeling uncertainties
are studied. Experimental results are included to evaluate the
validity and effectiveness of the proposed method.
Sun, 01 Jan 2012 00:00:00 GMThttp://hdl.handle.net/2117/175812012-01-01T00:00:00Z